In a manufacturing process of a semiconductor device, electrical characteristics of the semiconductor device are inspected by a semiconductor testing apparatus at the end of a pre-process or a post-process, so that faults of chips are inspected. In such a semiconductor testing apparatus, a probe apparatus serves as a handling apparatus that interfaces the chips on the semiconductor wafer, and a tester in charge of signal processing when performing an inspection at wafer state or at wafer level. Typically, the probe apparatus includes a movable mounting table (chuck top) configured to mount and support thereon the semiconductor wafer; a probe card having probe needles to be brought into contact with electrodes of each chip, thus allowing the chips to be electrically connected with the tester; and a moving device configured to move the mounting table to align the inspection target chips with respect to the probe needles or to the probe card fixed at a certain position.
A voltage (a breakdown voltage or a rated voltage) treated in a semiconductor device for power supply, i.e., a so-called power device, such as a power MOSFET or IGBT may be greatly differed depending on the purposes of use. For example, the power device may treat a voltage ranging from about 100 V to about 200 V in electronic home appliances, whereas the power device may treat a very high voltage ranging from about 600 V to about 1000 V in cars or industrial appliances. In railroad vehicles or power transmission and distribution systems, the power device may treat several thousands of voltages or higher.
Accordingly, when conducting inspection of electrical characteristics of a power device at wafer level in the semiconductor testing device, a voltage suitable for the power device may be applied from the tester to terminals on individual inspection target chips (power devices) on a wafer via the probe needles. If, however, the voltage applied for inspecting the chips is high, a spark (electric discharge) may be generated in the vicinity of a surface of the wafer, so that adjacent chips (power devices) may be damaged. This problem is more conspicuous in a SiC power device than in a Si power device.
Recently, a SiC power device is attracting attention as a next-generation power device having a compact size, a high breakdown voltage and a low loss. Since, however, a chip of the SiC power device is small-sized, a gap between electrodes on the chip is narrow, and a spark may be easily generated between a probe needle that applies a high voltage and a probe needle that applies a low voltage, or between a high-voltage probe needle and an electrode on an adjacent chip. Further, since it is difficult to forma protection circuit within the small-sized chip, the chip is weak for the spark.
To solve this problem, there is known a breakdown voltage inspecting apparatus (see, for example, Patent Documents 1 and 2). In this technique, an entire surface of a semiconductor wafer is covered with a liquid having higher insulation property than the atmosphere, or a surface of a inspection target chip is locally covered with such an insulating liquid on the wafer. Then, a breakdown voltage test is conducted by bringing a probe needle into contact with an electrode of the inspection target chip covered with the insulating liquid.
In such a breakdown voltage inspecting apparatus, since a leading end of the probe needle comes into contact with the electrode of the inspection target chip in the insulating liquid, a spark may not be generated from the probe needle, so that the inspection can be safely conducted even in a test in which a high voltage equal to or higher than several thousands of voltages is applied.    Patent Document 1: Japanese Patent Laid-open Publication No. 2003-100819    Patent Document 2: International Publication No. WO2010/021070
However, if the configuration of covering the entire surface of the semiconductor wafer with the insulating liquid (Patent Document 1) and the configuration of locally covering only the surface of the inspection target chip on the wafer (Patent Document 2) are adopted to an actual breakdown inspecting apparatus or a probe apparatus, a device or a control device for handling the insulating liquid on the wafer may be complicated, though the degree of complication may be differed therebetween. Further, an inspection time may also be lengthened.